The present invention relates to the general field of gas turbines and it relates more particularly to the configuration of a gearbox for driving accessories of a gas turbine.
The field of application of the invention is that of gas turbines for airplane or helicopter engines, and also for auxiliary power units (APUs).
The gas turbine engines of airplanes or helicopters generally include a gearbox for driving a plurality of turbine accessories or pieces of auxiliary equipment, such as in particular various pumps for producing hydraulic energy, for feeding fuel, for lubrication, electricity generators for producing electrical power, etc. Such a gearbox is commonly referred to as an accessory gearbox (AGB).
In known manner, a gearbox for driving accessories comprises one of more gear trains, each made up of a plurality of toothed wheels that are driven in rotation by a power transmission shaft, which shaft is coupled to a shaft of the turbine. Each accessory is generally mounted against one of the side faces of the gearbox and includes a drive shaft that is coupled to one of the toothed wheels of the gear train(s). When the turbine is in operation, a fraction of the mechanical power that it generates is taken from the turbine shaft and is transmitted via the power transmission shaft and the gear trains to the various accessories mounted on the gearbox in order to actuate them.
Accessory drive gearboxes vary in particular as a function of the number and the nature of the accessories to be driven. When designing an accessory drive gearbox, it is nevertheless important to keep down the size and the weight of the gearbox to as small as possible, in particular by acting on the positioning of the accessories relative to one another as a function of their individual sizes and of their speeds of rotation. Unfortunately, presently-known accessory drive gearboxes generally present size and weight that are excessive.